本文根据 Devhints / Q.js 翻译。代码示例及版本范围沿用原文。
关于
创建 Promise (Q.promise)
Q.promise (ok, fail) =>
asyncFunction ->
if error
fail new Error("Failure")
else
ok(data)针对数组
promises = [saveDisk(), saveCloud()]
# When all succeeds, or *at least one* error
Q.all(promises).done ->
alert "Saved"
# Same, but get the values
Q.all(promises).spread (a, b) ->
alert "Result A:" + a
alert "Result B:" + b
# When all either succeeds or errors
Q.allSettled(promises).done -> ...从 Node 创建 Promise
# Works like .call() or .apply()
Q.nfcall(FS.readFile, 'foo.txt', 'utf-8')
.then -> ...
Q.nfapply(FS.readFile, ['foo.txt', 'utf-8'])
.then -> ...
Q.npost(FS, 'readFile', ['foo.txt, 'utf-8'])
.then -> ...
Q.npost(FS, 'readFile', 'foo.txt, 'utf-8')
.then -> ...
readFile = Q.denodeify(FS.readFile)
readFile('foo.txt').then -> ...Promise 转 Node 异步操作
createUser = (next) ->
promiseMaker()
.nodeify(next)Promise 语法糖
# Shortcut for .then(ok, fail, progress)
promise
.then (data) ->
.catch (err) ->
.progress (percent) ->Try
Q.try -> promise()
.catch (e) -> console.error “Oh well”, e